As described in U.S. Patent Application Publ. No. 20170013781 to Flickinger, which is incorporated by reference herein in its entirety, an agricultural harvester known as a “combine” is historically termed such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating and cleaning. A combine includes a header, which removes the crop from a field, and a feeder housing which transports the crop matter into a rotary threshing and separating system.
The rotary threshing and separating system includes one or more rotors which extends axially (front to rear) or transversely within the body of the combine, and which is partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the rotor within the concave. Coarser non-grain crop material such as stalks and leaves are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop material such as chaff, dust, straw, and other crop residue are discharged through the concaves and fall onto a grain pan where they are transported to a cleaning system.
A transition cone is positioned between the feeder housing and the concave. The transition cone directs the gathered crop material toward the rotor cage while narrowing, acting as a funnel for the gathered crop material toward the rotor.
A prior art rotary threshing and separating system is shown in FIG. 1. Referring now to FIG. 1, which is reproduced from U.S. Patent Application Publ. No. 20170013781 to Flickinger, a prior art rotor assembly 72 which can be included in a threshing and separating system is shown and generally includes a rotor 74 defining a longitudinal axis A1, a concave 76 partially surrounding the rotor 74 and having perforations formed through, and a transition cone 80 connected to the concave 76 at a connection point 82 and defining an infeed to the rotor 74 from, for example, a feeder housing.
The transition cone 80 has a frusto-conical shape defined about the longitudinal axis A1 that ends abruptly at the connection point 82 between the transition cone 80 and the rotor cage 76. The transition cone 80 has a tapering diameter along its length so that as the transition cone 80 approaches the connection point 82, the transition cone 80 narrows.
The transition cone 80 includes a series of vanes 88 disposed along its inner surface for directing the crop material toward the reduced clearance W1 between the rotor 74 and the connection point 82. The vanes 88 guide the crop material as it travels along a conical spiral trajectory within the cone 80. It should be understood that the cone 80 remains fixed in position as the rotor 74 rotates about its axis to deliver crop material through the cone 80 and the concave 76.
Each vane 88 has a conical spiral shape, and extends from the inlet of the cone 80 to the outlet of the cone 80. The vanes 88 are uniformly spaced apart in a radial manner about the longitudinal axis A1, and are arranged at an equal pitch about the longitudinal axis A1. The first ends of the vanes 88 at the inlet end of the cone 80 are uniformly spaced apart about the inlet end of the cone 80, and, the second ends of the vanes 88 at the outlet end of the cone 80 are uniformly spaced apart about the outlet end of the cone 80. Such an arrangement of vanes is also disclosed in U.S. Pat. No. 6,830,512 to Tanis, for example (see vanes 61), and FIG. 3 of U.S. Pat. No. 4,148,323, which are each incorporated by reference herein in their entirety.
In operation, the incoming crop material initially travels in a linear fashion up the feeder housing (see item 20 of U.S. Patent Application Publ. No. 20170013781 to Flickinger). The majority of crop material then enters the inlet end of the transition cone 80 over a defined arc of about 180 degrees, which is significantly less than the 360 degree circumference of the inlet end of the cone 80. The crop material transitions from a linear motion to a rotary motion as it enters the cone 80 and travels between adjacent vanes 88 of the cone 80.
The vanes 88 compress the crop material as it transitions from a larger circumferential area at the inlet of the cone 80 to a smaller circumferential area at the outlet of the cone 80. The compressed crop material ultimately exits the cone 80 over a 180 degree exit area and enters the threshing chamber.
Because the arc length of the crop material at the inlet end of the cone 80 is greater than the arc length of the crop material at the outlet end of the cone 80, due to the geometry and position of the vanes 88, the crop material becomes compressed as it travels through the cone 80. It has been found that the rotary threshing system can have difficulty in managing the compressed crop material in an efficient manner.
To improve threshing performance and machine capacity, it would be desirable to deliver crop material from the 180 degree inlet portion of the transition cone and discharge the crop material over a larger discharge area, i.e., greater than 180 degrees. Stated differently, it would be desirable to increase the arc length of the crop material as it travels through the cone 80, and thereby limit compression of the crop material.
What is needed in the art is a threshing and separating system that experiences lowered crop pressure between the transition cone and the threshing chamber. Based on the foregoing reasons, there is a need for improved threshing and separating systems that address multiple objectives, including but not limited to increased energy efficiency and better control over crop flow through the threshing and separating system.